What is Biodiversity Net Gain (BNG)?

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As COP27 draws to a close the state of our natural environment continues to grab headlines and spark protests closer to home. Now therefore seems like a topical time for developers, Local Planning Authorities and land owners to revisit the upcoming coming into force of the requirement to provide BNG in Part 6 of the Environment Act 2021.

Being prepared and informed will allow you to remain agile in this emerging industry and highlight areas where BNG is already having an impact. So what do we need to know now about BNG (or ‘biodiversity gain’ as the 2021 Act names it)?

What is BNG?

The Environment Act 2021 will be introducing a new requirement for BNG where permission is applied for under the Town and Country Planning Act 1990, as ever subject to certain exceptions. The minimum BNG requirement currently means a 10% measurable improvement to biodiversity in connection with the development. The requirement will be imposed by the coming into force of section 98 and schedule 14 of the 2021 Act.

BNG will be secured by automatic mandatory planning conditions in Grampian form which will require a biodiversity gain plan to be submitted to and approved by the Local Planning Authority before commencement of development.

BNG must be obtained and maintained for at least 30 years under the said planning conditions, or planning obligation or conservation covenant.

Practically, BNG can be achieved by:

  • On-Site Units: Increasing or improving habitats on the site itself;
  • Off-Site Units: Increasing or improving habitats off-site. This option provides opportunities for private land owners who can improve biodiversity on their land to ‘sell’ the credits to local developers (such as via habitats banks) and we are already seeing this in the market; or
  • Purchasing Statutory Credits: This will be a government scheme used to deliver large biodiversity projects across England. This option is intended to be a last resort for developers where on-site and off-site mitigation is not possible and is likely to be a more expensive option.

Units will be measured using the ‘biodiversity metric’. The biodiversity metric is still being developed following a DEFRA consultation and is expected to be published at the end of 2022.

The starting point for measuring on site development is the pre-development biodiversity value of the onsite habitat – the baseline if you will. This will either be set;

  • at the date planning permission is granted; or
  • at an earlier date not pre-dating the date the provisions come into force (by agreement between the applicant and the Local Planning Authority).

There is a mechanism to prevent any tactical pre-devaluing of the biodiversity on the site before development. Where activities carried out on land after the 30 January 2020 in breach of the permission result in a reduction of the onsite habitat value, the biodiversity value is taken as being immediately before the works were carried out.

The biodiversity gain register will be used to record off-site biodiversity gain. This is a publicly accessible register for recording and verifying off-site biodiversity units which will also prevent double counting by showing site allocations for units.

BNG Implementation

Whilst the relevant parts of the Environment Act 2021 are not yet in force, they are estimated to be introduced in phases starting from November 2023 for planning permissions under the Town and Country Planning Act 1990. It is therefore crucial that developers, Local Authorities and private landowners prepare for its implementation now. Indeed many are already doing so as a result of development plan policy that already requires BNG (albeit under the auspices of policy rather than direct law) as noted below.

On that note, the National Planning Policy Framework and supporting guidance already encourage adoption of policies and decisions which contribute to and enhance the natural environment and provide biodiversity net gains. Whilst in of itself the NPPF cannot be used by Local Planning Authorities to mandate BNG policies per se, it is an important material consideration in planning decisions (Paras 2 and 218 of the NPPF).

A number of Local Authorities have already updated their Local Plans to incorporate requirements for BNG, and of course planning applications are then determined under those plans. As we get ever closer to the official coming into force of the legal BNG requirements under the Environment Act 2021 no doubt more authorities will adopt a similar approach.

November 2023 may seem far away, and already there is plenty of material available on BNG and what it means, but even so there is a sense that the significance of this requirement has not yet fully hit home. Developers, Local Planning Authorities and private landowners should therefore start ensuring they have the infrastructure and support in place for BNG requirements as soon as possible. Where BNG land is required off site for example, the legal agreements required with the land owners may take time to put in place.

For more information, please contact our Planning team who will be able to assist and advise you on the new requirements and how you can make sure you are BNG ready.

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